1. Field of the Invention
The present invention relates to methods for preparing bromofluorenes, which are useful as intermediate products or functional resins.
2. Description of the Related Art
For preparing bromofluorenes, methods are known which use halogenated hydrocarbons as solvents to brominate fluorene compounds. These methods are published in, for example, the following literatures: A. Sieglitz, Ber. Dtsch. Chem. Ges., 53, 1232 (1920); G. Hallas, J. D. Hepworth, D. R. Woring, J. Chem. Soc. (B), 975 (1970); C. J. Kelley, A. Ghiorghis, J. M. Kaurffman, J. Chem. Reserch(S), 446 (1997); M. Ranger, D. Rondeau, M. Leclerc, Macromolecules, 30, 7686 (1997); F. K. Sutcliffe, H. M. Shahidi, D. Patterson, J. Soc. Dyers Colour, 94 (7), 306 (1978); and R. Wu, J. S. Schumm, D. L. Pearson, J. M. Tour, J. Org. Chem., 61 (20), 6906 (1996).
Methods are also known which use organic solvents other than halogenated hydrocarbons, such as dimethylformamide. These methods are published in, for example, the following literatures: M. Ranger, D. Rondeau, M. Leclerc, Macromolecules, 30, 7686 (1997); and D. M. Johansson, M. Theander, T. Granlund, O. Inganas, M. R. Andersson, ibid., 34, 1981 (2001).
However, halogenated hydrocarbons have deleterious effects on the environment and the handling of such organic solvents is burdensome. Other solvents also have a problem in that it is enormously costly to dispose of them and waste water containing the solvents.